Submicron thin film inductive head with self-aligned staggered pole-tips

Abstract

A thin film inductive head having staggered pole-tips with a self-aligned recording gap region. The recording gap region is bounded by stepped pole-tip element with the steps made large with respect to the gap thickness. The pole-tip layers extend back from the air bearing surface to form a throat region that is also large with respect to the gap thickness. The self-aligned staggered pole-tip geometry is suitable for submicron track widths because the pole-tips may themselves be much wider and the self-aligned configuration avoids submicron masking and registration difficulties. The stepped pole-tip surfaces also eliminate the side-writing problem known in the art for overlapping thin film poles.

We claim: 
     
       1. A thin film magnetic head comprising: an air bearing surface (ABS) for contacting a magnetic storage medium;   a transducing gap formed between pole-tip surfaces separated by a gap distance;   a gap centerplane intersecting said ABS at a gap centerline and extending into said head from said ABS;   a recording gap region disposed in said gap centerplane, said recording gap region extending over a gap width along said gap centerline and extending from said ABS into said head over a throat height disposed substantially normal to said gap centerline;   a first pole-tip layer of ferromagnetic material disposed on one side of said gap centerplane and having a first stepped surface disposed facing said gap centerplane and separated therefrom within said recording gap region by a half-gap distance and elsewhere separated from said gap centerplane by a first step distance substantially greater than said half-gap distance; and   a second pole-tip layer of ferromagnetic material disposed on the other side of said gap centerplane overlapping said first pole-tip layer and having a second stepped surface disposed facing said gap centerplane and separated therefrom within said recording gap region by said half-gap distance and elsewhere separated from said gap centerplane by a second step distance substantially greater than said half-gap distance.   
     
     
       2. The magnetic head of claim 1 wherein: said first pole-tip layer overlaps said second pole-tip layer only in said recording gap region, thereby forming a staggered pole head.   
     
     
       3. The magnetic head of claim 2 wherein: said throat height exceeds 400% of said half-gap distance.   
     
     
       4. The magnetic head of claim 3 wherein: said first step distance is greater than 500% of said half-gap distance.   
     
     
       5. The magnetic head of claim 4 wherein: said second step distance is greater than 500% of said half-gap distance.   
     
     
       6. The magnetic head of claim 1 wherein: said throat height exceeds 400% of said half-gap distance. 
     
     
       7. The magnetic head of claim 1 wherein: said first step distance is greater than 500% of said half-gap distance.   
     
     
       8. The magnetic head of claim 7 wherein: said second step distance is greater than 500% of said half-gap distance.   
     
     
       9. The magnetic head of claim 1 wherein: said first stepped surface includes a step that is substantially normal to said gap centerplane.   
     
     
       10. The magnetic head of claim 9 wherein: said second stepped surface includes a step that is substantially normal to said gap centerplane.   
     
     
       11. A magnetic data storage device for storing data in and retrieving data from a magnetic medium, said device having at least one thin film magnetic head, said magnetic thin film head comprising: an air bearing surface (ABS) for contacting a magnetic storage medium;   a transducing gap formed between pole-tip surfaces separated by a gap distance;   a gap centerplane intersecting said ABS at a gap centerline and extending into said head from said ABS;   a recording gap region disposed in said gap centerplane, said recording gap region extending over a gap width along said gap centerline and extending from said ABS into said head over a throat height disposed substantially normal to said gap centerline;   a first pole-tip layer of ferromagnetic material disposed on one side of said gap centerplane and having a first stepped surface disposed facing said gap centerplane and separated therefrom within said recording gap region by a half-gap distance and elsewhere separated from said gap centerplane by a first step distance substantially greater than said half-gap distance; and   a second pole-tip layer of ferromagnetic material disposed on the other side of said gap centerplane overlapping said first pole-tip layer and having a second stepped surface disposed facing said gap centerplane and separated therefrom within said recording gap region by said half-gap distance and elsewhere separated from said gap centerplane by a second step distance substantially greater than said half-gap distance.   
     
     
       12. The magnetic data storage device of claim 11 wherein: said first pole-tip layer overlaps said second pole-tip layer only in said recording gap region, thereby forming a staggered pole head.   
     
     
       13. The magnetic data storage device of claim 12 wherein: said throat height exceeds 400% of said half-gap distance.   
     
     
       14. The magnetic data storage device of claim 13 wherein: said first step distance is greater than 500% of said half-gap distance.   
     
     
       15. The magnetic data storage device of claim 14 wherein: said second step distance is greater than 500% of said half-gap distance.   
     
     
       16. The magnetic data storage device of claim 11 wherein: said throat height exceeds 400% of said half-gap distance.   
     
     
       17. The magnetic data storage device of claim 11 wherein: said first step distance is greater than 500% of said half-gap distance.   
     
     
       18. The magnetic data storage device of claim 17 wherein: said second step distance is greater than 500% of said half-gap distance.   
     
     
       19. The magnetic data storage device of claim 11 wherein: said first stepped surface includes a step that is substantially normal to said gap centerplane.   
     
     
       20. The magnetic data storage device of claim 19 wherein: said second stepped surface includes a step that is substantially normal to said gap centerplane.